Pyrrolo[2,1-c][1,4]benzodiazepine antitumour antibiotics are commonly known as anthramycin class of compounds. In the last few years, a growing interest has been shown in the development of new pyrrolo[2,1-c]benzodiazepines (PBDs). These antibiotics react covalently with DNA to form an N2-guanine adduct that lies within the minor groove of duplex DNA via an acid-labile animal bond to the electrophilic imine at the N10-C11 position (Kunimoto, S.; Masuda, T.; Kanbayashi, N.; Hamada, M.; Naganawa, H.; Miyamoto, M.; Takeuchi, T.; and Unnezawa, H. J. Antibiot., 1980, 33, 665.; Kohn, K. w. and Speous, C. L. J. Mol., Biol., 1970, 51, 551.; Hurley, L. H.; Gairpla, c. and Zmijewski, M. Biochem, Biophys. Acta., 1977, 475, 521,; Kaplan, D. J. and Hurley, L. H. biochmestry, 1981, 20, 7572). The molecules have a right-handed twist, which allows them to follow the curvature of the minor groove of B-form double-stranded DNA spanning three base pairs. Recently, PBD dimmers have been developed that comprises two C2-exo-methylene substituted DC-81 subunits tethered through their C-8 position I an inert propanedioxy linker (Gregson, S. J.; Howard, P. W; Hartely, J. A.; Brooks, N. a.; Adams, L. J.; Jenkins, T. C.; Kelland, L. R. and Thurston, D. E. J. Med Chem. 2001, 44, 737). A recent development has been the linking of two PBD units through their C-8 positions to give bisfunctional alkylating agents capable of cross-linking DNA (Thurston, D. E.; Bose, D. S.; Thomson, a, S; Howard, P. W.; Leoni, A; Croker, S. J; Jenkins, T. C.; Neidle, S. and Hurley, L. H. J. Org. Chem., 1996, 61, 8141). Recently, a noncross linking mixed inmine-amide PBD dimmers have been synthesized that have significant DNA binding ability and potent anti tumour activity. (Kamal, A,; Ramesh, G.; Laxman, N; Ramulu, P,; Srinicas, O.; Neelima, K.; Kondapi, A. K.; Srinu, V. B,; Nagarajaram, H. M. J. Med. Chem. 2002, 45, 4679). These imine-amide PBD dimers have the structures shown below: 
Naturally occurring pyrrolo[2,1-c][1,4]benzodiazepines belong to a group of antitumour antibiotics derived from Streptomyces Species. Recently, there is much impetus for the PBD system as they can recognize and bind to specific sequence of DNA. Examples of naturally occurring PBDs include anthramycin, DC-81, tomaymycin, sibiromycin and neothramycin.
However, the clinical efficacy for these antibiotics is hindered by several limitations, such as poor water solubility, cardiotoxicity, development of drug resistance and metabolic inactivation. There is therefore, a urgent need for such antibiotics which do have the disadvantages of the prior art.